Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual era a superfície no jogo com Margit Rüütel Anett Schutting como oponente?
 ###Tabelas: CREATE TABLE squad_information (squad_information_id AUTO_INCREMENT PRIMARY KEY, Nat. VARCHAR, Name VARCHAR, Since VARCHAR, App(L/C/E) VARCHAR, Goals(L/C/E) VARCHAR, Ends INT, Transfer fee VARCHAR) CREATE TABLE fed_cup_doubles_performances_10 (fed_cup_doubles_performances_10_id AUTO_INCREMENT PRIMARY KEY, Edition INT, Zone VARCHAR, Round VARCHAR, Date VARCHAR, Against VARCHAR, Surface VARCHAR, Partner VARCHAR, Opponents VARCHAR, Result VARCHAR) CREATE TABLE english_open (english_open_id AUTO_INCREMENT PRIMARY KEY, Year Location VARCHAR, Mens Singles VARCHAR, Womens Singles VARCHAR, Mens Doubles VARCHAR, Womens Doubles VARCHAR) CREATE TABLE bischofshofen (bischofshofen_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Name VARCHAR, Nationality VARCHAR, 1st (m) VARCHAR, 2nd (m) VARCHAR, Points VARCHAR, Overall FHT Points VARCHAR, Overall WC points (Rank) VARCHAR) CREATE TABLE stations_under_construction (stations_under_construction_id AUTO_INCREMENT PRIMARY KEY, Station VARCHAR, Extension VARCHAR, City/Neighborhood VARCHAR, Projected opening INT, Transit Connections VARCHAR, Park and ride? VARCHAR)  
SELECT Surface FROM fed_cup_doubles_performances_10 WHERE Opponents = margit rüütel anett schutting